[Bug preprocessor/109183] [regression?] since GCC 11.1, -MM -MMD generates "a-" prefixed dependency files

[allan.w.macdonald at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109183

--- Comment #6 from Allan W. Macdonald <allan.w.macdonald at gmail dot com> ---
(In reply to Allan W. Macdonald from comment #5)
> Here is a workaround:

or just 

gcc -E -MMD test.c > /dev/null

if gcc-11 is default gcc.